<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>倒计时时钟</title>
</head>
<link rel="stylesheet" href="./css/index.css">
<script src="./js/index.js"></script>
<body>
<center>
    <div id="div">
        <ul id="time">
            <li>01</li><span>分</span>
            <li>40</li><span>秒</span>
        </ul>
        <div class="clear"></div>
        <input type="button" value="启动" id="btn">
    </div>
</center>
</body>
</html>